[asdf-devel] Pushed manual cleanups

[Faré]

On Fri, Feb 28, 2014 at 9:18 AM, Robert P. Goldman <rpgoldman at sift.info> wrote:
> I have pushed another quick set of modifications; all grammar and
> punctuation, with some chopping up by adding new subsections.
>
Uh, I don't see anything new on branch master.
If you didn't push, can you rebase to master and push?
I did a few minor modifications.

> In doing
> so, I stumbled on the following passage under Upgrading ASDF:
>
> Starting with ASDF 3 (2.27 or later),
> this self-upgrade will be automatically attempted as the first step
> to any system operation, to avoid any possibility of
> a catastrophic attempt to self-upgrade in midflight.
>
> It's not clear to me from the context what "this self-upgrade" refers
> to, nor how it's triggered.
>
> Is this because all systems have an implicit requirement of :depends-on
> ASDF?  So that when ASDF scans its registry it finds any new version and
> automagically updates it?
>
Yes, any system that extends ASDF in any way implicitly depends on ASDF,
yet most fail to declare a dependency on ASDF. What is worse, any system
with an explicit dependency on ASDF, or worse, defsystem-depends-on on
something that depends on ASDF, may cause ASDF to be reloaded
*in the middle of the build* if ASDF hasn't been upgraded yet.
Detecting in advance whether or not ASDF will be loaded is Halting-complete,
and so we have two safe options: detect such midbuild upgrade and fail,
and be a huge nuisance to users for no gain, or uprade preemptively
and have things just work.

Therefore, ASDF3 assumes that a user means an upgrade if and only if
he has configured a recent ASDF in his registries. I believe this
actually minimizes user cognitive load while maximizing functionality.

PS: as an example of enjoying scripting with Lisp,
see the new release.lisp script in cl-launch.
I suppose the asdf/bin/asdf-builder script could similarly be slightly
simplified
and improved by using the latest cl-launch 4 and inferior-shell 2.

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